Rule-governed activity vs. rule-creating activity

Questioning the usual understanding of Native American religions as supernaturalistic, this study re-examines the ritual system of the Yaqui people of Arizona. First, it evaluates assumptions about the nature of religion—including God, grace, and prayer—which inform the ethnographical interpretation of Yaqui religion. Second, it reconstructs the Yaqui cosmological system and relates their complex cosmos to the traditional religious actors, the Deer Dancer and the Pascola clowns. Third it examines the master symbol, Sewa or Flower, to demonstrate that Yaqui religious logic does not correspond to the grace theory of Catholicism. Fourth, it demonstrates that flower embodies a causal system in which all religious actors, human and transcendent beings alike, achieve ritual efficacy in mutual, reciprocal acts of witnessing. Finally, the essay observes that ‘conversion’ fails to make sense of Yaqui syncretism for two related reasons. In the first place, the Yaqui neither rejected the world nor embraced a monotheism which assigns a privileged, vertical superiority to God. In the second, the Yaqui applied traditional insights deriving from the most basic realm of myth to reach an understanding that Jesus and Deer are alike powerful innocents who sacrifice themselves so that others might live. In all these ways, the essay demonstrates that the concept of the supernatural fails to explain either the traditional or the Christian sides of Yaqui religion and suggests that the same may be true for other Native American religions as well.     

Foveal spatial summation in human cone mechanism

We measured at the fovea the chromatic contrast threshold for stimuli modulated along different chromatic directions in the isoluminant plane of MBDKL colour space, considering the two cardinal axes (L/M) and S/(L + M) and other intermediate non-cardinal directions. This psychophysical determination was conducted as a function of stimulus size. The test stimulus was a foveal isoluminant Gaussian patch with a raised cosinusoidal temporal profile superimposed on a neutral background. The task was performed binocularly. The increment threshold was measured for three observers by a Bayesian adaptive psychometric method (QUEST). The Ricco area of complete spatial summation was estimated from the threshold-versus-area curves. The perceptive fields are smaller for the L/M-cone opponent direction than the S/(L + M)-cone opponent. The perceptive field sizes for the stimuli in non-cardinal chromatic directions and stimuli modulated at the (L/M)-cone opponent direction present similar values. Measurements were made at two luminance levels, 5 and 40 cd m(-2), but the differences found were small. The perceptive field sizes found could be associated with LGN area.     

Computation of cone contrasts for color vision research

Cone-contrast coordinates have proved useful for representing transient test stimuli used in color vision experiments. These representations automatically take into account the spectral absorption of cones and any Weberian adaptation to steady fields of light. Under these conditions, they also can be interpreted as being an approximation to the incremental cone response. A detailed methodology is presented for making appropriate measurements and calculations of cons contrasts for any light source, especially color monitors.     

Schedule-induced locomotor activity in humans.

In two experiments, humans received tokens either on a fixed-interval schedule for plunger pulling or various response-nondependent fixed-time schedules ranging from 16 to 140 seconds. Locomotor activity such as walking, shifting weight, or pacing was recorded in quarters of the interreinforcement interval to examine the induced characteristics of that behavior in humans. While performance was variable, several characteristics were present that have counterparts in experiments with nonhumans during periodic schedules of food reinforcement: (a) first quarter rates, and sometimes overall rates, of locomotor activity were greater during intervals that terminated in a visual stimulus and token delivery than those without: (b) overall rates of locomotor activity were greater during fixed-time 16-second schedules than during fixed-time 80- or 140-second schedules; (c) rates of locomotor activity decreased during the interreinforcement intervals; (d) locomotor activity was induced by response-dependent and response-nondependent token delivery. These results showed that the rate and temporal pattern of locomotor activity can be schedule-induced in humans.     

Hypnagogic imagery and EEG activity.

The relationships between hypnagogic imagery and EEG activity were studied. 7 subjects (4 women and 3 men) reported the content of hypnagogic imagery every minute and the hypnagogic EEGs were classified into 5 stages according to Hori's modified criteria. The content of the hypnagogic imagery changed as a function of the hypnagogic EEG stages.     

Reinforcing value of physical activity as a determinant of child activity level.

This study examined whether the relative reinforcing value of physical activity (RRVPA) measured in the laboratory predicted physical activity measured in the natural environment in 32 6-11-year-old children. RRVPA correlated with physical activity level (r = .42, p < .05), and contributed to the prediction of physical activity level along with child obesity. RRVPA was related to the number of moderate to vigorous physical activity exercise bouts (r = .35, p < .05), not to the duration of those bouts. These results suggest that RRVPA is a determinant of child physical activity level, and that it may be naturally more reinforcing for children to engage in multiple, short exercise bouts than fewer, more extended bouts.     

Affect, personality, and social activity.

These studies examined relations between social activity and state and trait measures of Positive and Negative Affect. In Study 1 Ss completed scales relevant to 3-factor models of personality and a weekly mood and social activity questionnaire for 13 weeks. In Study 2 Ss completed measures of the 5-factor model of personality and a daily mood and social activity survey for 6-7 weeks. In within- and between-Ss analyses, socializing correlated significantly with state measures of Positive Affect and with trait measures of Extraversion/Positive Emotionality. These relations were relatively general across various types of positive affect and social events; however, specific types of social events also were differentially related to affect. In contrast, social activity had no consistent association with measures of Negative Affect or the other personality dimensions. The results support a temperamental view of Extraversion.     

Apparent height of a stereokinetic cone is decreased by departure from circularity

Subjects made judgements of the comparative height of the stereokinetic cones seen for pairs of rotating figures with varying eccentricity and ellipticity. For any given eccentricity, ellipticity of the figure reduced the apparent height, with narrow ellipses seeming to be shallower. The effect is attributed to an interaction in constancy scaling.     

Cognitive aspects of mental activity during sleep.

Upon nighttime experimental awakening of 27 subjects in four sleep conditions (sleep onset early; sleep onset late; Stage 2; and rapid eye movement, REM, sleep), 108 dream reports and their association reports were collected. Dream reports were analyzed for length (temporal units) and content categories (continuity; implausibility; presence of the dreamer [i.e., "the self"], a setting, characters). Associations were classified as episodic, abstract self-referred, and semantic memories. The two sets of results tend to show a basic homogeneity among mentation reports in the four sleep conditions considered. These findings are interpreted as supporting the hypothesis that the same cognitive mechanisms operate, at different levels of engagement, in dream generation rather than the hypothesis of multiple dream-generation systems dependent upon the physiological characteristics of the various sleep stages.     

Physiological activity in an attribute learning task.

The relationship between the amount of information processing in an Attribute Learning task and autonomic activity, measured by skin conductance response (SCR), was investigated. The amount of information processing was manipulated by type of concept and feedback. Furthermore, the influence of practice and verbalization was studied.Three types of concepts were used: conjunction, exclusion and joint denial. The stimulus population consisted of four three-valued dimensions. The results showed that (1) SCR did not differ among concepts; (2) SCR varied with type of feedback, it being smallest at blanks and largest at infirming feedback; (3) SCR was related to the number of confirmations preceding infirmation; (4) subjects mainly used the strategy ‘reject hypothesis only after infirmation’; (5) subjects usually selected not-yet-tested hypotheses; (6) practice influenced performance; (7) verbalization did not result in more efficient use of information; however, the appropriateness of the experimental set-up to study this factor was questioned; (8) conjunction was easier to learn than the other concepts. The results were discussed in terms of uncertainty reduction, resulting from testing hypotheses in a concept learning task.     

Perceived environmental predictors of physical activity over 6 months in adults: activity counseling trial.

PURPOSE: In the present study, the authors extend previous cross-sectional findings by using a prospective design to determine whether physical and social environmental characteristics predict physical activity over 6 months. DESIGN: Inactive adults were recruited to the Activity Counseling Trial, a multicenter, randomized, controlled trial of physical activity intervention in primary care. Participants were 387 women and 474 men aged 35-75 years in 3 regions; 1/3 were minorities; 56% had some college education. Baseline perceived environmental variables were used to predict physical activity at 6 months, adjusting for experimental condition and other potential moderators. MEASURES: The validated 7-day physical activity recall interview was used to estimate minutes of moderate to vigorous physical activity. A standardized survey was used to measure social and physical environmental variables around the home and neighborhood. RESULTS: Women reporting no unattended dogs and low crime in their neighborhoods and men reporting frequently seeing people being active in their neighborhoods did 50-75 more minutes of physical activity per week than did those with different environmental characteristics. Interactions of environmental variables with age group suggested that older adults may be more affected by environmental variables than are younger adults. CONCLUSIONS: Self-reported social and physical environmental variables were significantly related to moderate to vigorous physical activity among a diverse sample of adults living in 3 regions of the United States. These prospective findings strengthen the conclusion from previous cross-sectional studies that environmental variables are important correlates of physical activity.     

Precuneus-prefrontal activity during awareness of visual verbal stimuli.

Awareness is a personal experience, which is only accessible to the rest of world through interpretation. We set out to identify a neural correlate of visual awareness, using brief subliminal and supraliminal verbal stimuli while measuring cerebral blood flow distribution with H(2)(15)O PET. Awareness of visual verbal stimuli differentially activated medial parietal association cortex (precuneus), which is a polymodal sensory cortex, and dorsolateral prefrontal cortex, which is thought to be primarily executive. Our results suggest participation of these higher order perceptual and executive cortical structures in visual verbal awareness.